Temperature responsive valve device



Dec. 21, 1954 R. M. KENDIG 2,697,554

TEMPERATURE RESPONSIVE VALVE DEVICE 7 142 5 5e 77 7 1mm 141/145 151/ 1761 I l V 112 180 114 155 1'70 154 A 1 2 1 f k\ i3? I INVENTOR.RoberfMKendg BY ATTOPNEY' United States P ent TEMPERATURE RESPONSIVEVALVE DEVICE Robert M. Kendig,

house Air Brake sylvania Pittsburgh, Pa., assignor to Westing- Company,a corporation of Penn- 3 Claims. (Cl. 236-79) This invention is adivision of my copending application Serial No. 157,909, filed April 25,1950 and relates to a temperature responsive valve device and moreparticularly to such a device for effecting variations in pressure of acontrol fluid according to temperature of such as gas turbine combustiongases.

A prime object of the invention is to provide a quickacting temperatureresponsive valve device which will elfect delivery of a controlledpressure of fluid in direct proportion to the temperature of the mediumbeing sensed.

Other objects and advantages of the invention will become apparent fromthe following more detailed description taken in connection with theaccompanying drawing in which the single figure is a schematicrepresentation in cross-section of a temperature responsive valve deviceembodying the invention.

DESCRIPTION The temperature responsive valve device comprises apneumatic pyrometer to provide fluid at a pressure di-' rectlyproportional to the temperature of hot expansible gases being suppliedto a gas turbine, and an anticipating relay valve means for controllinga fluid pressure communication between the pneumatic pyrometer and adevice to be controlled.

The pneumatic pyrometer comprises a'ca singhaving a fluid pressuresupply chamber 110 formed therein which is adapted to receive fluidunder pressure from such as a pipe 44 by way of a casing passage 111. Aresilient diaphragm 112 is provided, clamped at its outer peripherybetween two portions of the casing. The diaphragm 112 is subjectopposingly to pressure of fluid in a chamber 113 at one side and topressure of fluid in a chamber 114 at its opposite side. A supply valve115 is provided,

disposed in the supply chamber 110 for controlling communication througha casing bore 116 extending from said supply chamber to the chamber 113.The valve 115 is operably connected to the diaphragm 112 through themedium of a stern 117 extending through the bore 116. One end of thestem 117 is attached to the valve 115 while the opposite end rockablyrests in a follower element 118 carried by the diaphragm. A tapered coilspring 120 disposed in the supply chamber 110 is arranged to urge thestem 117 into engagement with the follower element 118. The diameter ofthe stem 117 is considerably less than the diameter of the bore 116 toallow for flow of fluid under pressure in the clearance spacetherebetween while at the same time allowing for self-alignment of thevalve 115. The tapered spring 120 abuts a casing shoulder at its largerend and abuts the valve 115 at its opposite end so that the valve isthereby centered relative to an opening 122 of the bore 116 which opensinto the chamber 110. Proximity of the valve 115 to the opening 122determines the flow area which 'will be available to the fluid underpressure in chamber 110 for flow through bore 116 into chamber 113. Acompression spring 124, disposed in the chamber 114, is arranged to biasthe diaphragm 112 in the direction of chamber 113. One end of the spring124 is located in an annular recess formed in the casing while itsopposite end abuts a diaphragm follower which is provided with a centralprofrom chamber jecting portion 126 around which the respective end of Ithe spring fits for location thereby. A passage 128 communicates betweenthe chambers 113 and 114 forconveying fluid under pressure from theformer to the latter. A needle valve 130 is provided in passage 128 toregulate the volume of fluid under pressure which may flow from chamber113 to chamber 114. Needle valve 130 is attached to a stem inscrew-threaded attachment with the casing and projecting outwardlythereof. The outer end of the stem may be turned manually to advance orwithdraw the needle valve 130 into and out of an opening 131 which formsa part of passage 128 at its junction with chamber 113. The areapresented to fluid under pressure from chamber 113 for flow to chamber114 may thus be carefully adjusted for reasons which will hereinafterbecome obvious.

In order to sense the temperature of a medium such as the hot expansiblegases of a gas turbine, as a chosen example, capillary tube or tubes 133attached to the casing are provided for projection into the path of flowof such gases. The tubes 133 provide continuous restricted passages 134which open the chamber 114 to the atmosphere. In the case of hotexpansible gases at high velocity and pressure, the tubes 133 should bearranged to extend into the path of travel of such gases witharrangement made for the ends of the tubes to discharge to atmosphere.The tubes 133 are constructed of heat resistant material in order towithstand the hot combustion gases and are of suflicient strength towithstand shock and vibration caused by the hot gases passing over themat high velocity. A tube (not shown) of larger internal diameterprovided with a choke at its outer projecting end might be substitutedfor the plurality of smaller tubes 133.

Operation of above described portion of temperature sensitive device Inoperation of the pneumatic pyrometer portion of the device, with thesupply chamber connected to a source of fluid at a substantiallyconstant pressure and with the tubes 133 extending through the path offlow of hot expansible gases entering the gas turbine, and with thevalve 115 disposed a distance away from opening 122, fluid underpressure from the supply chamber 110 will flow via the unseated valveand the bore 116 into the chamber 113. With the needle valve disposed acer'-. tain distance away from opening 131, fluid under pressuresupplied to chamber 113 will flow by way of such opening and the passage128 into the chamber 114,"frorn' which a leak to atmosphere will occurby way of passages 134 in tubes 133. According to a feature of theinvention, with the constant bias imposed on the dia phragm 112 by thespring 124, the pressure of fluid in the chamber 113 will be maintainedat a certain constant value greater than any pressure which may exist inthe chamber 114; that is, through deflection of diaphragm 112 andthereby movement of valve 115, greater or lesser amounts of fluid underpressure from the supply chamber 110 will flow into chamber 113, asnecessary to maintain the constant pressure diflerential across needlevalve 130 between chambers 113 and 114 against the leak to atmospherethrough tubes 133. By virtue of the constant differential in pressurethus maintained between chambers 113 and 114, for any given adjustedposition of the needle valve 130, the volume of fluid flowing 113 viasaid needle valve into chamber 114 thence to atmosphere by way of tubes133 will be constant during equal time intervals. Pressure of fluid intubes 133, hence in chamber 113, will be directly proportional to thetemperature of such fluid, which temperature will depend upon andindicate the temperature exposed to the hot gases, and certainly to agreater heat transfer coefficient. The constant volume flow method thusaffording pressure variations directly proportional to changes intemperature being sensed simplifies calibration of the device andgreatly reduces error over previous pneu 3 matic pyrometers of avariable flow type in WhlCh pressure By employment of "such.

varied approximately as the square root of the temperature, introducingpossibility of considerable error at'the higher temperatures where equalincrements in temperature change produce increasingly greater incrementsin resultant pressure change.

Description of relay portion of temperature sensitive device Theanticipating relay portion of the device comprises a casing secured tothe casing of the pyrometer portion in such fashion that the supplychamber 110 is common to both and provides a compact assemblage. A bore140 1n the casing is provided to communicate between the supply chamber110 and a delivery chamber 141 which is constantly open to a fluidpressure control passage 142 formed in the casing. A supply valve143 isdisposed in the supply chamber 110 for controlling communication betweensaid supply chamber and the delivery chamber 141 by way of the bore 140.A tapered seat is formed in the asing around the end of bore 140 Openinginto the chamber 110 to accommodate the supply valve 143. A compressionspring 145 disposed in the supply chamber 110 is arranged to urge thesupply valve 143 toward a seated position in which it is shown in thedrawing/ A stem 147 of lesser diameter than the diameter of the bore 140through which it extends is attached at its one end to the supply valve143 to act as a medium through which same may be unseated against actionof spring 145. The opposite end of the stem 147 is disposed in thedelivery chamber 141 and is tapered to form an exhaust valve 148. Anexhaust valve seat element 150, disposed opposite to and in alignmentwith the exhaust valve 148, is provided, attached at its one end to amovableabutment 151 disposed within acavity 152 formed in-the casing.The movable abutment 151 is reciprocably connected to the casing throughattachment at its outer peripheral edge to one end of a bellows 153, theopposite end of which is attached to the casing at one end of cavity152. A fluid pressure exhaust chamber 155 is defined by the inner wallof cavity 152, exteriorly of the movable abutment 151, and bellows 153.Exhaust chamber 155 is constantly open to the atmosphere by way of anexhaust port 156 opening outwardly through the casing. A bellows 158 isattached at its one end to a projecting end of seat element 150 and atits opposite end to the casing encircling the opening to'thebore 140.The bellows 158 allows for reciprocable movement of the seat element 150along with abutment 151 and defines an'outer wall of the deliverychamber 141 and an inner wall of an annular bellows chamber 160 withinbellows v153 between a left-hand end wall of cavity 152 and one face ofthe abutment 151. The bellows chamber 160 is constantly open to thecontrol passage 142 by way of a needle valve 161 which is adjustableexteriorly of the casing to vary the area available for flow of fluidunder pressure between passage 142 and the bellows chamber 160. Anexhaust passage 162, opening into the exhaust chamber 155 through theabutment 151, extends longitudinally through the seat element 150 to anopening disposed opposite to the exhaust valve 148. A tapered seat isformed in the projecting end of the, seat element 150 to accommodate theexhaust valve 148. i

For actuating the seat element 150 and thereby stem 147 and supply valve143 a stem 170 is provided which is attached to a resilient diaphragm171 by means of the usual diaphragm follower elements suitably attachedthereto. The diaphragm may be suitably clamped at its periphery betweentwo portions of the casing and is subject opposingly to pressure offluid in a control chamber 175 at one side and to pressure of fluid in achamber 176 at its opposite side which latter chamber is constantly opento atmosphere via such as a port 177. A casing partition separateschamber 155 from chamber 176 and an opening is provided therein throughwhich the stem 170 extends with clearance.' A socket'180-is formed inone face of the abutment to receive the end of the stem 170 which isrounded or tapered to fit the socket to assure transmission of thrust tothe abutment when in chamber 175 acting on diaphragm 171.

in engagement therewith. A compression spring 185, dis- Y posed inchamber 176 is arranged to bias the diaphragm 171 in the direction ofchamber 175 toward a rest position in which it is shown in the drawingand in which the respective diaphragm follower abuts a centrallyprojecting tip of a portion of the casing forming an end wall 186 of thecontrol chamber 175. In rest position of the diaphragm 171, theprojecting end of stem 170 connected theretowill'be disposed a shortdistance away from the abutment 151. The control chamber 175 in theanticipating relay portion of the device 4 is constantly open by way ofa casing passage 190 to the chamber 114 in the pneumatic pyrometerportion of the device. It will be seen, therefore, that pressure offluid in the control chamber 175 will be the same as that existing inchamber 114 and will therefore be directly proportional to temperatureof the capillary tubes 133, hence to the temperature of the hot gasesentering the gas turbine.

Operation of relay portion of temperature sensitive device In operationof the anticipating relay portion of the device in conjunction with thepneumatic pyrometer portion, until the pressure of fluid in the controlchamber 175 attains a value suflicient to overcome the bias of thespring 185, the diaphragm 171 will remain in its rest position with thestem 170 out of engagement with the abutment 151 which will be in theposition in which it is shown in the drawing with seat element 150 outof contact with the exhaust valve 148, and the supply valve 143,therefore, will be in its seated position in which it is shown in thedrawing. With the supply valve 143 closed, fluid under pressure in thesupply chamber cannot reach the delivery chamber 141 and with theexhaust valve 148 open said delivery chamber will be vented toatmosphere by way of the'passage 162 in seat element and attachedabutment 151, exhaust chamber and the port 156. Passage 142 and therebybellows chamber will be vented to atmosphere by way of the bore 140 andthe delivery chamber 141, as will be appreciated from precedingdescription.

When the pressure of fluid in the control chamber 175, corresponding toa certain temperature of the capillary tubes 133 and hence of theturbine gases, becomes sufficient to overcome opposition of the spring185 the diaphragm 171 will be deflected in the direction of chamber 176to cause engagement of stem with the abutment 151, after which saidstern and abutment in moving with continued slight additional deflectionof the diaphragm will move seat element 150 into seating engagement withthe exhaust valve 148, thereby closing oil? the delivery chamber 141,hence passage 142 and bellows chamber 160 to the atmosphere.

In employing the device to prevent increase in temperature of turbinegases above a certain maximum allowed temperature, in a manner as willhereinafter be described, the needle valve 130 will be adjusted so thatpressure of fluid in chambers 114 and will cause closing of the exhaustvalve 148 at a temperature of tubes 133 somewhat less than the maximumallowed temperature of the gases passing over the tubes. The needlevalve 130 is so adjusted in order to assure that the anticipating relayportion be brought into operation before the maximum allowed temperatureof the gases is reached as the temperature of the capillary tubes 133,hence pressure in connected chambers 114 and 175, will lag thetemperature of tliile gases'when the latter temperature is increasingrapt y.

When'the pressure of fluid in chamber 175, corresponding to temperatureof the capillary tubes 133, increases above that necessary to seat theexhaust valve 148, resultant further deflection of the diaphragm 171against spring 145, through movement of the stem 170, abutment 151,attached seat element 150, and the stem 147,will cause unseating of thesupply valve 143. Fluid under pressure from the supply chamber 110 willthen fiow by way of the unseated supply valve 143 and bore 140 into thedelivery chamber 141 and control passage 142 and, by way of needle valve161, into the bellows chamber 160 where the pressure of such fluidacting on the abutment 151 will act to oppose action of pressure offluid When the pressure of fluid in the bellows chamber 160 actingonabutment 151, together with action of springs 145 and 185, becomessufiicient to overcome action of the pressure of fluid in the chamber175, the abutment 151 will move in the direction of chamber 155,carrying the stem 170 with it and thereby allowing spring 145 to seatthe supply valve 143 while the exhaust valve 148 remains seated.Pressure of fluid in the passage 142 and delivery chamber 141 is thusheld by closure of the supply valve 143.

When the temperature of the hot gases passing over the tubes 133increases slowly, the temperature of these tubes will be the same asthat of the gases and will increase at the same relatively slow rate,and, it will be appreciated, that the pressure of fluid in chambers 114and 175 therefore will be directly proportional to the temperature ofthe hot gases and will increase at the same slow rate. Under theseconditions, once the supply valve 143 is unseated by action of pressureof fluid in chamber 175, resultant flow of fluid from the supply chamber110 into passage 142 will have sufficient time to flow into the bellowschamber 160 to increase the pressure of fluid therein at the same rateas the increase in pressure in chamber 175, and the action of such pressure in chamber 160 on abutment 151 will be such as will maintain thevalve 143 positioned to maintain pressure of fluid in passage 142 indirect proportionality to pressure of fluid in chamber 175, hence indirect proportionality to the temperature of the tubes 133 and thereforeof the hot gases, in the present instance.

'When the temperature of the hot gases increases very rapidly, there maybe instantaneous diflerences between the temperature of the tubes 133and that of the gases as' the tubes warm up to gas temperature. Thetemperature of the tubes 133, hence pressure of fluid in chambers 114and 175, under the assumed condition, will therefore no longer bedirectly proportional to the rapidly increasing temperature of the hotgases. The rate of increase in temperature of the tubes 133, hence therate of increase in pressure in chambers 114 and 175, will reflect thediscrepancy between the temperature of the tubes and the temperature ofthe gases, in other words, the rate at which the temperature of thetubes 133 and the pressure in chamber 114 and 175 will change in a giveninstant is a measure of the amount of difference between the temperatureof the tubes and that of the gases and so indicates the temperaturetoward which the tubes are headed. Then once the supply valve 143 isinitially unseated by action of the pressure of fluid in chamber 175which is increasing in rate as above described, fluid under pressurewill flow into the passage 142 and by way of the needle valve 161, willflow into the bellows chamber 160 to oppose the action of pressure offluid in chamber 175. By virtue of the needle valve 161, a suflicientrestriction to path of flow will be imposed on fluid flowing frompassage 142 to bellows chamber 16%) that the instantaneous pressure offluid supplied to passage 142 will exceed that in the bellows cham ber160. The amount that the pressure of fluid in passage 142 is allowed toexceed pressure of fluid in the bellows chamber 160 will depend upon therate of change in pressure in chamber 175, hence rate of change intemperature of the tubes 133, which, as previously mentioned, was anindication of the gas temperature toward which the tubes were headed. Byproper adjustment of the needle valve 161, the pressure of fluid inpassage 142 will be substantially maintained at a direct proportionalityto the rapidly changing temperature of the turbine gases even though thetemperature of the tubes 133 lags that of the gases by a substantialtime interval.

Conversely, with both the supply valve 143 and the exhaust valve 148closed to hold a pressure of fluid in passage 142 in accord with astable temperature of tubes 133, when the temperature of the gases dropsslowly, the temperature of the tubes 133 will be that of the gases andwill drop correspondingly as will pressure of fluid in the chambers 114and 175. Such reduction in pressure in the chamber 175 will allow spring185 and pressure of fluid in bellows chamber 160 to effect movement ofabutment 151 so that seat element 150 will leave the exhaust valve 148.Fluid under pressure will then release from bellows chamber 160 andpassage 142 at substantially the same rate until pressure of fluid inchamher 175 is again preponderant over force of spring 185 and pressureof fluid in the bellows chamber 160, whereupon, through deflection ofdiaphragm 171, movement of stem 170 in engagement with abutment 151 willcause reseating of element 150 on valve 148.

If, reduction in temperature of the turbine gases occurs at a ratefaster than can be followed by the tubes 133, such reduction, reflectedby a pressure drop in the chamber 175, will result in unseating of theelement 150 from exhaust valve 148 to allow for reduction in pressure inpassage 142. The action of needle valve 161 on release of fluid underpressure from the bellows chamber 160 will be such as to allow pressureof fluid in the passage 142 to reduce in direct proportionality withreduction in temperature of the turbine gases in anticipation of thetemperature toward which the temperature of the tube 133 is headed asindicated by the rate of change of the latter temperature.

Whether or not the drop in temperature of the tubes 133, hence drop inpressure in chamber 175, occurs rapidly, once the pressure of fluid inchamber 175 drops and remains below the value required to maintain theseat element 150 in engagement with valve 148 against opposition ofspring and pressure in bellows chamber 160, the diaphragm 171 willdeflect in the direction of chamber 175 to allow element 150 to unseatand remain unseated from valve 148, venting passage 142 to atmospherevia chamber 141, passage 162, chamber and port 156.

It will be seen that the device will respond to an increase intemperature of the turbine gases above a desired maximum value to effectsupply of fluid to control passage 142 at a pressure or pressuresdirectly proportional to the temperature of such gases, whetherincreasing. or decreasing above said maximum value and will respond to adecrease in temperature of the gases below the maximum value to effectventing of the control passage 142 to atmosphere.

SUMMARY It will now be seen that I have provided a relatively simpletemperature responsive valve device which will effect rapid delivery ofa controlled pressure of fluid in direct proportion to the temperatureof a medium being sensed.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent, is:

l. A pneumatic pyrometer device comprising a casing having a fluidpressure supply chamber adapted to be connected to a source of fluidunder pressure and also having a cavity, a resilient diaphragm disposedin said cavity to define a deflectable partition dividing said cavityinto a first fluid pressure chamber and a second fluid pressure chamber,said casing having a first fluid pressure communication extendingbetween said fluid pressure supply chamber and said first chamber andhaving a second fluid pressure communication extending between saidfirst fluid pressure chamber and said second fluid pressure chamber,valve means arranged to control degree of opening and closing of saidfirst fluid pressure communication and attached for movement withdeflection of said diaphragm, flow restricting means in said secondcommunication, spring means arranged to bias said diaphragm in thedirection of said first fluid pressure chamber, a restricted tubularelement attached at its one end to said casing and opening into saidsecond fluid pressure chamber, at least a portion of said tubularelement being adapted for exposure on its exterior surface to action ofa heat zone, and a passage opening from said second fluid pressurechamber for connection to pressure responsive temperature indicatingmeans.

2. A temperature sensitive device comprising a restricted tubularelement for conveying fluid under pressure through a heat zone, meansdefining a fluid pressure supply chamber adapted to receive fluid underpressure from a source thereof, means defining a fluid pressurecommunication having an inlet connected to said supply chamber and anoutlet connected to said tubular element, flow restricting means in saidcommunication, valve means controlling supply of fluid under pressurefrom said supply chamber to said inlet, and biased diaphragm meanssubject opposingly to pressures in said communication at opposite sidesof said flow restricting means and operatively connected to said valvemeans to maintain pressure of fluid in said communication at the inletside of said flow restricting means constantly a certain degree greaterthan pressure of fluid existlng in said communication at the outlet sideof said flow restricting means as the latter pressure varies in directproportion to temperature of said tubular element.

3. A pressure responsive valve device comprising a casing having formedtherein in series along an axis of symmetry common to each, a supplychamber adapted to be connected to a source of fluid under pressure, afluid pressure exhaust chamber constantly open to atmosphere and adiaphragm chamber, a first partition integral with said casing disposedbetween the supply and exhaust chambers-and having a supply openingextending therethrough coaxial with the chambers and having a taperedsupply valve seat exposed to said supply chamber and encircling saidsupply opening, a second partition integral with said casing disposedbetween the exhaust and diaphragm chambers and having astem-accommodating opening extending therethrough in coaxial alignmentwith said supply opening, a supply valve in said supply chamber having atapered shoulder for self-aligning seating engagement with said taperedsupply valve seat, a bias compression spring in said supply chamber inabutting relationship at its opposite ends with said casing and withsaid supply valve, respectively, to urge the latter toward said supplyvalve seat, a valve stem rigidly attached at its one end to said supplyvalve and extending with clearance through said supply opening, atapered exhaust valve attached to the opposite projecting end of saidvalve stem, a disk-shaped movable abutment disposed in said exhaustchamber coaxial therewith, said abutment having an exhaust passageextending from its center radially outward to its outer peripheral edgeand a central socket formed in a face constantly exposed to said exhaustchamber, a first cylinder-shaped bellows member disposed in said exhaustchamber coaxial therewith having opposite ends in sealed attachment withsaid first partition and with said movable abutment to define the outerperipheral wall of an anticipation control chamber, a cylinder-shapedexhaust valve seat element disposed in said first bellows memberattached at its one end to said movable abutment coaxial therewith andprojecting into proximity of said exhaust valve, said seat elementhaving a central exhaust communication extending longitudinallytherethrough into junction with the exhaust passage in said movableabutment and having a tapered exhaust valve seat formed in itsprojecting end in encirclement of the open end of said communication, asecond cylinder-shaped bellows member within said first bellows membercoaxial therewith having opposite ends in sealed attachment with saidfirst partition in encirclement of said supply opening and with saidseat element in encirclement of said exhaust valve seat, respectively,to define the inner peripheral wall of said anticipation control chamberand the outer peripheral wall of a delivery chamber, said casing havinga delivery passage constantly open to said delivery chamber by way ofthe clearance space between said valve stem and the wall of said supplyopening and being adapted for connection to a device to be controlled,said casing also having an anticipation control communication extendingbetween said delivery passage and said anticipation control chamber, aflow restricting element disposed in said anticipation controlcommunication adjustable externally of said casing to regulate degree ofrestriction, a defiectable circular diaphragm means secured at its outerperiphery to said casing disposed within said diaphragm chamber incoaxial alignment therewith and dividing the interior thereof into acontrol chamber adapted to receive fluid at variable pressures on itsone side and an atmospheric chamber open to the stem-accommodatingopening in said second partition on its opposite side, an actuatingstern attached for movement with deflection of said diaphragm meansextending through said atmospheric chamber and through said stemaccommodating opening into proximity. of said movable abutment withinsaid exhaust chamber, the projecting end of said actuating stem beingtapered for self-aligning contact with the socket formed in the centerof said abutment, and a control compression spring encircling saidactuating stem and abut ting at its opposite ends said second partitionand said diaphragm means to act thereon in opposition to action ofpressure of fluid in said control chamber. H

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date,

339,756 Frew Apr. 13, 1886 773,684 Speller -2 Nov. 1, 1904 1,630,318Tate May 31, 1927 2,409,871 Krogh Oct. 22, 1946 2,512,561 Ziegler June20, 1950 2,524,445 Ifield. Oct. 3, 1950 2,606,420 Moore Aug. 12, 1952FOREIGN PATENTS Number Country Date 90,639 Sweden Oct. 26, 1937

